Why Australia's Binar CubeSats Burned Out Early: Solar Activity's Devastating Impact on Satellites

Three small Australian CubeSats from Curtin University’s Binar Space Program—Binar-2, Binar-3, and Binar-4—ended their missions early. They were supposed to last six months, but they only lasted two. The reason? A sudden surge in solar activity.

How Solar Activity Affects Low Earth Orbit Satellites

Satellites in low Earth orbit (LEO) gradually lose altitude over time. Eventually, they re-enter the atmosphere and burn up. But recent solar activity has sped up this process.

Small satellites like the Binar CubeSats are more affected. They don’t have altitude control systems, so they can’t adjust their orbits.

Solar activity, such as sunspots, solar flares, and stronger solar winds, creates "space weather." This impacts both satellites and astronauts in orbit.

Key Factors Impacting Satellite Orbits

1. Solar Wind and Flares: Solar winds and flares add energy to the upper atmosphere, causing it to expand. This increases drag on satellites, making them lose altitude more quickly.

2. Solar Cycle 25: The Sun is currently at the peak of its 11-year solar cycle, leading to more solar activity than anticipated. This increased activity causes the atmosphere to expand further, which in turn affects the orbits of satellites.

3. Lack of Altitude Control: Unlike larger commercial satellites, the Binar CubeSats didn’t have thrusters to adjust their orbits. This made them more vulnerable to rapid orbital decay.

Broader Impacts of Solar Activity

Solar activity doesn’t only affect small research satellites.

Atmospheric Drag: Stronger solar winds affect both small satellites and large networks like Starlink. Commercial satellites can adjust their orbits, but this increases operational costs.

Satellite Electronics: Increased solar radiation can damage the electronics inside satellites. This leads to more technical problems and shorter lifespans for the equipment.

Auroras and Radiation: Solar activity intensifies auroras, making them visible farther from the poles. It also increases radiation levels, which can disrupt satellite communications.

Future of the Binar Space Program

Although Binar-2, 3, and 4 didn't last as long as planned, the Binar Space Program has gained valuable lessons.

The program will continue, with new CubeSats set to launch once solar conditions improve. Solar activity is expected to decrease by 2026, with a solar minimum around 2030.

Lessons and Opportunities

The Binar Space Program’s experience offers valuable lessons for future missions.

Understanding Space Weather: The lessons learned will help design satellites that can better withstand space weather.

Improved Design: Future CubeSats may be built to better handle solar activity.

Timing of Missions: With solar activity expected to decrease by 2026, future missions can be planned for more stable conditions.

The early loss of the Binar CubeSats highlights the challenges posed by an active Sun. However, it also offers valuable lessons.

Curtin University’s Binar Space Program is committed to advancing Australia’s space capabilities and improving the resilience of future satellites.